Rollicking, breathless docu “Big City Dick” carries the sense filmmakers Scott Milam, Ken Harder and Todd Pottinger may have needed a shoehorn to pack their wealth of material (and larger-than-life subject) into pic’s svelte, two-hour frame. An unqualified success in its world premiere at Slamdance (where it copped the Audience Award for best overall film) and subsequently shown to great acclaim at Santa Barbara, pic’s L.A. premiere Feb. 12 is part of the American Cinematheque’s Best of Slamdance program. A Gotham screening at the Two Boots Pioneer theater is slated for early March.

The product of some 10 years of work by two teams of filmmakers at first working independently, pic is an immersion into the day-to-day life of longtime Seattle street musician Richard Peterson, who has cut several albums.

Inspired equally by the musical stylings of Johnny Mathis and what Peterson calls “the background music era of the late 1950s and early 1960s” — theme from the old “Sea Hunt” TV series, as performed by the Ziv Symphony Orchestra, is a particular subject of fascination — Peterson’s albums sport such indelible titles as “The Second Album” and “Love on the Golf Course.”They’ve also earned their creator an improbable cult following. Among admirers: frequent REM sideman Scott McCaughy (who invited Peterson to jam with his own band, the Young Fresh Fellows) and the Stone Temple Pilots (who recorded a cover of one of Peterson’s tunes).

A stocky, baldheaded bear of a man with a freakishly charming gap-toothed smile and a speech impediment, Peterson is a grand eccentric.

Readily able to recall obscure historical dates and facts (particularly as concerns Mathis albums), Peterson sleeps with a petrified elephant trunk, has a fetish for long purple neckties and insists on measuring his musical success against the likes of Pearl Jam, Nirvana and Soundgarden. (“Richard Peterson is still on the street,” he declares indignantly.)

Peterson claims a coterie of “personality buddies”: friendships he has forged (and in some cases forced) with an array of local TV and radio stars, some of whom he visits daily, embracing them in suffocating hugs. This network includes Jeff Bridges (who Peterson met during the Seattle filming of “American Heart” and who he refers to as “the son of ‘Sea Hunt’ “) and, natch, Mathis (who Peterson regularly follows on tour, to the point security personnel have regarded him as a stalker).

What makes “Big City Dick” so remarkable is the way Milam, Harder and Pottinger avoid holding Peterson up as a subject for mockery or gawking. Rather, they’ve made a movie that respects their subject without sentimentalizing him.

Just when it seems “Big City Dick” is bound to run out of steam, pic adds to the Peterson mystique, introducing his elderly mother and offering insight into his complex family backstory: The illegitimate son of bass player Val Sayas, he was effectively disowned by his mother’s husband, and has little contact with his siblings.

There are also interviews with Bridges (who considers Peterson something of a musical prodigy) and the ordinarily reclusive Mathis (who doesn’t share Bridges’ enthusiasm, but claims to have made his peace with his No. 1 fan), as well as a segment devoted to Peterson’s high-water gig as house pianist at a now-defunct Seattle bar, and a wrenching chronicle of his ongoing battle with weight-related diabetes.

What emerges is a found epic about an indefatigable American original, and an oddly touching tribute to a vanishing vaudevillian spirit. Indeed, few who see “Big City Dick,” would deny Richard Peterson gives an audience its money’s worth.

Tech production is slick, with eye-catching montages of Peterson’s album covers, sheet music and other archival footage interspersed with confidently vid-lensed docu segs.